Water color paper before being used for water color painting must be wetted, then stretched and held till dry, and thereafter still held tightly while the water color artist paints. The process most commonly used today involves soaking the paper in water until it expands, then it is placed over and secured onto a painting board by gum taping its edges to the board. While drying the paper shrinks and thereby creates a taut, smooth water color painting surface. The paper, after it is stretched, remains secured to the board through the completion of the painting. If the paper becomes unsecured while wet and drying it buckles, and becomes wrinkled creating a difficult surface upon which to paint.
The gum-tape used to secure the water color paper is typically 2 inches wide, with 1 inch of width being used to contact the paper and the other 1 inch of width being used to contact the board. Typically the board is made of one-half to three-quarters of an inch thick plywood, and it is sized to be slightly larger than the water color paper to be stretched. Generally if the plywood board is less than one-half inch in thickness it may warp and/or rack with the forces caused by the drying and shrinking of the water color paper. It is not uncommon for the gum-tape to come loose during the drying process or later during the water color painting period. Extreme care was and is required in removing the painting to avoid tearing the water color paper and damaging the painting.